McHenry County Department of Health
Translate this page:

Health Department News

Press Enter to show all options, press Tab go to next option

Health Department reports Legionnaires' Disease

Post Date:07/10/2018 1:34 PM

Contact Keri Zaleski
815-334-4456; cell 815-236-3238

WOODSTOCK IL – McHenry County Department of Health (MCDH) reports that nine County residents were diagnosed with Legionnaires’ disease between June 7 and July 1.  The people who became ill are from various County localities and range in age from 46 to 82 years old.

Occurring more frequently in hot humid weather, Legionnaires’ disease is caused by a type of bacteria commonly found in the environment and is transmitted by aerosolization, which means you can become ill by breathing in a mist or vapor contaminated with the bacteria. Legionella bacteria is found naturally in freshwater environments like lakes and streams.  It can become a health concern when it is found in building water systems such as shower heads, hot tubs, fountains, hot water tanks and large plumbing systems.  

Legionnaire’s Disease symptoms typically begin 2-10 days after exposure and can include muscle aches, diarrhea, nausea, vomiting, fever and chills.  Shortness of breath, coughing, headache, or mental confusion can also be common.   "Legionnaires’ disease is not known to spread person to person,” said Illinois Department of Public Health Chief Medical Officer Jennifer Layden, M.D., PhD  “Most healthy people do not get Legionnaires’ disease after being exposed to Legionella bacteria.  Individuals at increased risk of developing Legionnaire’s disease include those older than 50 years of age, or who have certain risk factors, such as being a current or former smoker, having a chronic disease, or having a weakened immune system."

The Health Department is working closely with the Illinois Department of Public Health to investigate these occurrences. See your healthcare provider if you are symptomatic and think you have been exposed to Legionella bacteria.  For more information visit



Return to full list >>

Free viewers are required for some of the attached documents.
They can be downloaded by clicking on the icons below.

Acrobat Reader Flash Player Windows Media Player Microsoft Silverlight Word Viewer Excel Viewer PowerPoint Viewer